1. Field of the Invention
This invention relates in general to automatic container processing systems, and relates more particularly to systems for detecting jams or other malfunctions in the flow of containers through such systems.
2. Prior Art
Typically, container filling equipment contains a plurality of filling valves in process stations or pockets for receipt of a corresponding plurality of containers and for simultaneously filling these containers. The filled containers are then delivered to a conveyor for transport to sealing equipment which contains a plurality of sealers or seamers capable of simultaneously sealing a plurality of containers. In accordance with one prior art structure for filling containers, a rotary filling mechanism receives a succession of containers which are to be filled by placing each container in a pocket adjacent a filling valve capable of supplying the material to be placed in the container. After filling, the containers are transferred from the filler to a track and conveyed along the track to a sealer or seamer unit which contains a plurality of stations for sealing each of the containers.
In the operation of such equipment, it is important that the process flow smoothly and in an uninterrupted manner. If a malfunction occurs in the seamer line which results in an interruption or jam in the container flow, the results thereof can be disastrous. Current container processing equipment may operate at rates of 2000 containers per minute or higher, so that a jam of even a relatively short duration can result in the loss of a substantial quantity of filled product, as well as necessitating the shutdown of the processing equipment for cleanup.
One seemingly straightforward approach to jam detection involves counting the number of containers entering and the number leaving the process station and taking appropriate action, such as sounding an alarm or shutting down the process line, or both, if the input count exceeds the output count, presumably indicative of a malfunction or jam in the flow of containers through the process station. However, this approach does not take into account the fact that a certain amount of container loss in the processing system, such as an occasional crushed or broken container, is acceptable; what is to be avoided is a jam which results in a catastrophic loss of product and downtime. Also, this simple approach of comparing the count of containers in and containers out does not accomodate the initialization at starting of the process system where a significant number of containers may enter the system before any are detected at the output.